1. Technical Field
The present disclosure relates to a field emission device, a method for making the same, and an ion source using the same.
2. Description of Related Art
Field emission displays (FEDs) are a new, rapidly developing flat panel display technology.
Field emission devices are important elements in FEDs. A field emission device usually includes an insulating substrate, a cathode electrode located on the insulating substrate, a dielectric layer located on the cathode electrode defining a number of holes to expose the cathode electrode, a number of carbon nanotubes located on the exposed cathode electrode, and an anode electrode spaced from the cathode electrode. When a voltage is applied between the anode electrode and the cathode electrode, a number of electrons are emitted from the carbon nanotubes and strike the anode electrode through the holes. However, the electrons collide with free gas molecules in the vacuum and ionize the free gas molecules, thereby producing ions. The ions move toward the cathode electrode and bombard the carbon nanotubes exposed through the holes. The carbon nanotubes become damaged, thus causing the field emission device to have a short lifespan.
What is needed, therefore, is a method for making a field emission device that can overcome the above-described shortcomings.